/diy/ - Do It Yourself

Help /diy/ I am a bit confused.

I have a 5v regulator that works. It has 3 pins, vin, ground and when I input 3.6v in vin, it outputs 5v in vout. the circuit is picture 1.

In picture 2, I am using a pnp transistor to turn this regulator on and off. If I input 2.4v to base pin the transistor, it connects c to e. and I am using c as ground for my regulator circuit. so if transistor is on, the ground of my old circuit (in picture 1) is now connected real ground of the battery. if transistor is off (2.4v is not connected) then ground is unconnected and regulator/led powers off.

the problem is when I also put an arduino as a load on the regulator (picture 3), the arduino does not turn on. Why is that? It works if I remove the transistor and power the arduino using circuit 1.

I am suspecting that the transistor does not allow enough current to power arduino but I am not sure how to confirm that. If so how can I pick a better transistor?